Ionizing radiation typically has sufficient energy to remove electrons from orbits of atoms, thereby generating charged particles. Another type of radiation is non-ionizing radiation, which typically does not have sufficient energy to remove electrons from their orbits. Radiation in outer space typically includes ionizing radiation, which may be manifested as high energy, charged particles. Examples of ionizing radiation include gamma rays, protons, neutrons, and the like. Ionizing radiation may damage human tissues and cells, which can lead to cancer and/or death. Ionizing radiation may also damage instrument and communication systems on board space vehicles, stations, and the like.
The sun occasionally releases significant amounts of ionizing radiation as charged particles during events known as coronal mass ejectas (“CMEs”). The charged particles released during CMEs include electrons, protons, and heavy ions. Such ionizing radiation may severely damage human cells, as well as sensitive electronic components and other devices. Therefore, even though CMEs are relatively uncommon occurrences, the amounts of radiation they potentially inflict upon a crew and equipment of a spacecraft gives rise for a need to shield part or all of such spacecraft from such radiation.
Shielding from proton and heavy ion radiation may generally be accomplished by either absorbing the particles or by deflecting the particles. To absorb the radiation, materials having a thickness sufficient for the amount of energy expected from the radiation may be disposed around an area that houses the crew and/or sensitive equipment during a CME. However, because of the weight of such a housing, the use of radiation-absorbing material is typically impractical for space exploration and other applications. Additionally, the absorption of high energy particles releases a different form of radiation such as gamma rays and X-rays that pass through the shielding material and may harm the crew and/or equipment.
On the other hand, active radiation shielding deflects radiation particles instead of absorbing them. One example of active radiation shielding of CME radiation is the magnetosphere of the Earth, which creates a magnetic field of enough flux density to change the trajectory of such radiation particles from the sun or elsewhere, thereby causing the radiation to be diverted away from the Earth.
One known system for active radiation shielding uses an external solenoid magnetic field. Another known system for active radiation shielding includes a conductive ring through which electric current flows. A magnetic field is generated through the electric current flowing through the conductive ring.
However, known systems for active radiation shielding typically deflect ion particles only in certain directions. For example, one known system provides radiation protection in a single direction, while another known system leaves end areas of a spacecraft exposed and unprotected. Additionally, the known systems typically do not shield individuals and instruments from electromagnetic radiation within a spacecraft. Long periods of exposure to electromagnetic radiation adversely impact human health and instrument performance.